3Com OfficeConnect 3C16771, Руководство пользователя

Страница: 103 / 182

Policy Rules 103
You can disable logging of events which are usually written
to the Internet Firewall’s internal Screen Log. For example,
if LINUX’s authentication protocol is filling the log with
useless entries, you can configure the screen log to ignore
all activity for this service.
To disable screen logs for a specific service:
1
Highlight the service name in the list box.
2
Clear the Enable Logging check box
3 Click Modify .
To delete a service:
1
Highlight its name in the list box.
2
Click Delete Service .
For services with multiple entries, you can delete only a
single Port/Protocol combination from the list. For example,
deleting the entry marked
Name Service (DNS) [53,6]
deletes just the TCP portion of the service.
Policy Rules
Network Access Rules evaluate network traffic’s source IP
address, destination IP address, and IP protocol type to
decide if the IP traffic is allowed to pass through the
firewall. Custom rules take precedence, and may override
the Internet Firewall’s default state packet inspection.
The ability to define Network Access Rules is a very
powerful tool. Using custom rules, it is possible to disable
all firewall protection or block all access to the Internet. Use
extreme caution when creating or deleting Network Access
Rules.
Network Access Rules do not disable protection from
Denial of Service attacks, such as SYN Flood, Ping of Death,
LAND, and so forth. However, it is possible to create
vulnerabilities to attacks that exploit vulnerabilities in
applications, such as WinNuke.
Click
Policy
, and then select the
Policy Rules
tab. A window
similar to that in Figure 45 is displayed.